Small and medium-sized enterprises require a server system to process a large amount of information for implementing processing and storing function. Therefore, the server system may include one or more storage devices and one or more motherboards. However, the signal wires inside of the server system may be messy when the server system has a plurality of storage devices and a plurality of motherboards. Because the PCIe slot of the motherboard is connected to the hard disk module through the signal wire, it is inconvenient to unplug the signal wires before exchanging the motherboard by hot plugging.